Method of applying closure caps to containers



Sept. 1s, 1.928. 684,892

' J. E. S HARP METHOD OF APPLYING CLOSURE CAPS T0 CONTAINERS Original Filed June 4, 1924 WITNESSES INVENTOR flag? I ifz hwvamw Patented Sept. 18, 1928.

UNITED STATES PATENT OFFICE.

JOHN E. SHARP, OF NEW KENSINGTON, PENNSYLVANIA, ASSIGNOR TO ALUMINUM COMPANY OF AMERICA, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF APPLYING CLOSURE CAPS TO CONTAINERS.

Original application filed June 4, 1924, Serial No. 717,724. Divided and this application filcd January 29.

1927. Serial No. 164,580.

This invention relates to a method of applying closure caps to containers, such as bottles, jars and the like, and particularly to a method of spinning closure caps on threaded receptacles in a manner to produce an hermetic seal.

The present application is a division of my copending application Serial No. 717,724. filed June 4, 1924, for a machine for'applying closure caps to receptacles, which discloses a method of and apparatus for applying plain skirted closure caps to externally threaded receptacles by exerting pressure between a cap and the receptacle and simul-' taneously splnning a thread upon the cap skirt in conformity with the thread on the receptacle. V

The object of this invention is to provide an improved method for sealing receptacles to the end that an hermetic seal may be easily and quickly formed and applied, and that it may be so formed that it is easily removable.

Various methods for applying closure caps to receptacles have been heretofore proposed which function to conform closure caps to the threaded contour of receptacles to which they are applied. The principle of these prior art methods is analogous to a moldingoperation in that the thread of a receptacle is utilized as a matrix for forming a complementary thread on the skirt of a closure cap. Roller members have been provided-with threaded peripheries corresponding to the pitch and depth of a thread on a receptacle and used to press the metal of the closure cap 1nto engagement with the thread of the receptacle by a rolling action, the thread-forming operation taking place along the full vertical extent of the face of -the portion of the closure cap adjacent to the thread of the receptacle. Also closure caps have been applied by a split yieldable gripping member, usually made of rubber, disposed around a cap and contracted to press at one time upon the entire surface of the cap skirt and thereby distort and crimp it into conformity with the shape of the thread.

These methods are unsatisfactory because the displacement of a cap skirtinto the thread ofthe receptacle by simultaneously rolling or compressing the entire surface of the skirt causes the metal to expand in both directions with relation to the crests of the thread, and this finally results in relieving the pull upon the top of the cap and in correspondingly duninishing the hermetic character of the seal elfected while pressure isapplied to the top of the cap during the thread-forming operation.

- According to the present invention a closure cap is applied to an externally threaded receptacle by progressively displacing the cap skirt into the groove of the thread beginning at the top of the thread and terminating at its lower end. By this method the material'of the closure cap skirt is continuously pulled downwardly, that is to say away from the top of the cap, with the result that when the pressure applied to the top of the cap during the thread-forming operation is removed the threaded skirt continues to exert a. downward pull upon the top of the cap to maintain an hermetic seal. This progressive threading of a cap skirt while on a threaded receptacle is preferably effected by placing a planetary disc having a spinning face shaped like the groove of the receptacle thread adjacent to the upper end of the re 'ceptacle thread and in contact with the cap a receptacle having a plain. s'irted closure capapplied to it, and having a spining disc in the proper position to begin the spinning operation; Fig. 2 a similar view illustrating the relative position of the spinning disc and receptacle at the completion of the operation; and Fig. '3 a view partially in section and partially in elevation of a. spinning disc and its support for carrying on the spinning operation.

Having reference first to Fig. 1, the upper end or neck of the bottle 1, provided externally with a screw thread 2,.is shown as having applied to it a closure cap comp-rising atop 3 and a plain skirt 4 depending from the top and lying adjacent to thread 2, the skirt being of such length that when spun and stretched downwardly its lower edge will not overhang the bead below the thread on the container and will be supported by the upper side of the bead. During a thread-spinning operation pressure is applied to the top of the cap by a plunger 6 to effect an hermetic sealing of the top of the container by a gasket arranged between the tops of the receptacle and cap, the receptacle being suitably supported while this pressure is applied.

Adjacent to the cap skirt 4 there is shown a single planetary spinning disc 10 having a peripheral edge 11 which conforms substantially with the groove of thread 2, although in practice it is preferred to use a plurality of such discs spaced at equal angular intervals about the receptacle. As shown in Fig. 3 disc 10 may be attached to a shaft 12 rotatably mounted in the outer end of an arm 13, which arm is movable towards and from the receptacle in the manner fully disclosed in my said copending patent application. Shaft 12 is yieldingly urged upwardly by a spring 14which bears at one end upon a nut 15 attached to the upper end of the shaft and at its other end upon a collar 16 resting upon the outer end of arm 13. The arrangement here is such that when disc 10 is pressed u on the cap skirt 4 and relative rotation eiected between the container 1 and the disc, the disc following the groove of thread 2, moves downwardly against the compresion of spring 14.

At the beginning of a cap-applying operation the parts are in the relative position shown in Fig. 1, the disc being at the upper end of thread 2 and being pressed towards the cap skirt 4. Preferably the disc is rotated about the longitudinal axis of container 1, rather than container 1 being rotated about its longitudinal axis. When the disc is so rotated it rolls around the container and presses the metal of capskirt 4 into the groove of the thread progressively from the upper statutes, I have explained the principle and ,mode of operation of my invention, and have illustrated and described what I now consider to be the best manner in which it may be practiced. However, I desire to have it understood that, within the scope of the ap pended claims, the invention may be practiced otherwise than as specifically shown and described.

I claim:

1. The method of applying a closure cap to a recptacle having an externally screwthreaded top, which comprises placing a skirted cap on the receptacle, and progressively spinning a screw thread on the cap skirt beginning the thread at the upper and completing it at the lower threaded portion of the receptacle.

2. The method of sealing a receptacle having an externally screw-threaded top, which comprises placing a skirted cap on the top of the receptacle with the skirt of the cap adjacent to the thread of the receptacle, applying pressure to the top of the cap, and progressively spinning a screw-thread on the cap skirt beginning the thread at the upper and completing it at the lower end of the receptacle, whereby the skirt is progressively drawn downwardly-to hold the top of the cap in firm sealing engagement with the top of the receptacle.

In testimony whereof, I sign my name.

JOHN E. SHARP. 

